﻿using System;
using System.Text;
using System.Web.UI;
using Xpedite.Extensions;
using Xpedite.Resources.Combiners;
using Xpedite.WebAbstraction;

/* Copyright (c) 2010 CBaxter
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), 
 * to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, 
 * and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 
 * IN THE SOFTWARE. 
 */

namespace Xpedite.Resources.Definitions
{
  internal class SpriteDefinition : DefinitionBase
  {
    private static readonly INamingRule NamingRule = new NamingRule(NamingPattern.CssClass);
    private readonly IResourceUrlGenerator _urlGenerator;
    private readonly ICombinerFactory _combinerFactory;
    private readonly IResourceCache _resourceCache;
    private readonly ResourceType _resourceType;

    public override ResourceType ResourceType { get { return _resourceType; } }

    public SpriteDefinition(DefinitionArgs args, String referenceName, ResourceType resourceType)
      : base(args, referenceName, NamingRule)
    {
      Verify.NotNull(args, "args");
      Verify.True(resourceType == ResourceType.Png || resourceType == ResourceType.Gif || resourceType == ResourceType.Jpeg, "resourceType", "Value must be Gif, Jpeg or Png.");

      _resourceType = resourceType;
      _urlGenerator = args.UrlGenerator;
      _resourceCache = args.ResourceCache;
      _combinerFactory = args.CombinerFactory;
    }
    
    public override void EmitResource(HtmlTextWriter writer)
    {
      var transparentGif = new TransparentGif(_urlGenerator);
      _resourceCache.GetOrCreateWithNoDependency(
        transparentGif.ResourceUrl,
        () => transparentGif
      );

      IResourceUrl spriteVirutalUrl = _urlGenerator.GenerateUrlFor(this);
      _resourceCache.GetOrCreateWithResourceDependencies(
        spriteVirutalUrl,
        () => _combinerFactory.CreateSpriteCombiner(ResourceType).Combine(spriteVirutalUrl, this),
        Resources
      );

      IResourceUrl spriteCssVirutalUrl = _urlGenerator.GenerateUrlFor(this, ResourceType.Css);
      _resourceCache.GetOrCreateWithResourceDependencies(
        spriteCssVirutalUrl,
        () => _combinerFactory.CreateSpriteCssCombiner().Combine(spriteVirutalUrl, this),
        Resources
      );

      writer.RenderCssStyleSheetLink(spriteCssVirutalUrl);
    }

    #region Transparent Gif Resource

    private class TransparentGif : IResourceContainer
    {
      private static readonly String TransparentGifRootVirtualPath = WebHost.ApplicationVirtualPath + "/xpedite.sprite.xcr";
      private static readonly IResource TransparentGifResource = new Resource
      {
        Bytes = Convert.FromBase64String("R0lGODlhAQABAPc".PadRight(1041, 'A') + "CH5BAEAAP8ALAAAAAABAAEAAAgEAP8FBAA7"),
        Compressable = false,
        Type = ResourceType.Gif,
        Encoding = Encoding.Default,
        LastModified = new DateTime(DateTime.UtcNow.Year, 01, 01).ToUniversalTime()
      };

      private readonly IResourceUrl _resourceUrl;

      public TransparentGif(IResourceUrlGenerator urlGenerator)
      {
        Verify.NotNull(urlGenerator, "urlGenerator");

        _resourceUrl = urlGenerator.GenerateUrlFor(TransparentGifRootVirtualPath);
      }

      public ResourceType ResourceType
      {
        get { return ResourceType.Gif; }
      }

      public IResourceUrl ResourceUrl
      {
        get { return _resourceUrl; }
      }

      public IResource Resource
      {
        get { return TransparentGifResource; }
      }
    }

    #endregion
  }
}
